TWI815795B - Photocurable resin compotiosion, display device and a method of producing the display device - Google Patents

Abstract

The object of the present invention is to suppress the discoloration of polarizing plates in high-temperature environments.

The photocurable resin composition of the present invention is used for the cured resin layer 6 in the image display device 1 including the image display member 4 including the polarizing plate 2, the cured resin layer 6, and the translucent member 5 in this order, and is cured The moisture permeability of the latter photocurable resin composition when the thickness is 0.3mm is more than 400g/m ² /day in an environment of 40°C and relative humidity of 90%.

Description

Photocurable resin composition, image display device, and method of manufacturing image display device

This technology relates to a photocurable resin composition, an image display device, and a manufacturing method of the image display device. This application is based on and claims priority to Japanese Patent Application No. 2016-151290 filed in Japan on August 1, 2016, which is incorporated by reference into this application.

The image display device can be manufactured by the following method, for example (see Patent Document 1, for example). First, a photocurable resin composition is placed between the image display member and the translucent member to form a resin composition layer. Then, the resin composition layer is irradiated with light and cured to form a cured resin layer. As described above, the image display device is manufactured by bonding and laminating the image display member and the translucent member via the cured resin layer.

A conventional image display device 100 is, for example, as shown in FIG. 1 , and includes an image display member 4, a hardened resin layer 101, and a translucent member 5 in this order. The image display member 4 usually has a polarizing plate 2 formed on the viewing side surface of the image display unit 3 . The polarizing plate 2 is, for example, a laminated body in which the polarizing element 8 is sandwiched between a protected layer 9 and a protective layer 10 as shown in FIG. 2 .

The inventor of this case learned through research that the polarizing plate 2 of the conventional image display device 100 may change color in a high-temperature environment.

Prior technical literature patent documents

Patent Document 1: Japanese Patent Application Publication No. 2014-222350

The present technology is proposed in view of this conventional fact, and provides a photocurable resin composition, an image display device, and a method for manufacturing an image display device that can suppress discoloration of a polarizing plate in an image display device in a high-temperature environment.

The photocurable resin composition of the present technology is used as the cured resin layer in an image display device including an image display member, a cured resin layer and a translucent member in this order. The image display member includes a polarizing plate, and the cured photocurable The moisture permeability of the flexible resin composition when the thickness is 0.3mm is above 400g/m ² /day in an environment of 40°C and 90% relative humidity.

The image display device of this technology includes an image display member, a hardened resin layer, and a light-transmitting member in sequence. The image display member includes a polarizing plate, and the hardened resin layer has a moisture permeability of 40°C and a relative humidity of 90 when the thickness is 0.3mm. % of the environment is more than 400g/m ² /day.

The manufacturing method of an image display device of the present technology includes the following steps: the step of coating the above-mentioned photocurable resin composition on the surface of a light-transmissive member including a polarizing plate, or the surface of an image display member including a polarizing plate; The step of bonding the image display member and the light-transmitting member with the light-blocking curable resin composition; and the step of hardening the photo-curable resin composition.

According to this technology, the discoloration of the polarizing plate in the image display device can be suppressed in a high-temperature environment.

1‧‧‧Image display device

2‧‧‧Polarizing plate

3‧‧‧Image display unit

4‧‧‧Image display component

5‧‧‧Transparent components

6‧‧‧Hardened resin layer

7‧‧‧Light shielding layer

8‧‧‧Polarizing element

9‧‧‧Protective layer

10‧‧‧Protective layer

11‧‧‧Photocurable resin composition

12‧‧‧Photocurable resin composition layer

13‧‧‧Temporarily hardened resin layer

14‧‧‧TAC layer

15‧‧‧PVA layer

16‧‧‧TAC layer

17‧‧‧Acrylic adhesive layer

18‧‧‧Polarizing plate

19‧‧‧Glass plate

20‧‧‧Photocurable resin composition

21‧‧‧Glass plate

22‧‧‧Glass joint

23‧‧‧Hardened resin layer

24‧‧‧Image display device

25‧‧‧hardened resin layer

26‧‧‧Calcium chloride

27‧‧‧cup

100‧‧‧Image display device

101‧‧‧hardened resin layer

FIG. 1 is a cross-sectional view showing an example of an image display device.

FIG. 2 is a cross-sectional view showing an example of a polarizing plate used in an image display device.

3 is a cross-sectional view showing an example of step (A) of the manufacturing method of the image display device.

FIG. 4 is a cross-sectional view showing an example of step (B) of the manufacturing method of the image display device.

FIG. 5 is a cross-sectional view showing an example of step (C) of the manufacturing method of the image display device.

FIG. 6 is a cross-sectional view showing an example of step (AA) of the manufacturing method of the image display device.

7 is a cross-sectional view showing an example of step (BB) of the manufacturing method of the image display device.

FIG. 8 is a cross-sectional view showing an example of step (BB) of the manufacturing method of the image display device.

FIG. 9 is a cross-sectional view showing an example of steps (CC) of the manufacturing method of the image display device.

FIG. 10 is a cross-sectional view showing an example of step (DD) of the manufacturing method of the image display device.

FIG. 11 is a schematic cross-sectional view of the polarizing plate.

Fig. 12 is a schematic cross-sectional view of the glass joint body.

FIG. 13 is a cross-sectional view schematically showing an image display device for testing.

Figure 14 is a diagram for explaining the method of moisture permeability test.

<Photocurable resin composition>

The light-curing resin composition of this embodiment has a moisture permeability of 400 g/m ² /day or more, preferably 500 g/m ² /day, when the cured thickness is 0.3 mm in an environment of 40°C and 90% relative humidity. or above, more preferably 600 g/m ² /day or more, further preferably 700 g/m ² /day or more. In addition, the upper limit of the moisture permeability after curing of the photocurable resin composition is not particularly limited, but may be, for example, 1000 g/m ² /day or less. Here, the so-called moisture permeability refers to the moisture permeability measured in an environment of 40°C and 90% relative humidity in accordance with JISZ0208. By using the photocurable resin composition having such a structure, discoloration of the polarizing plate 2 in the image display device 1 shown in FIG. 1 can be suppressed in a high-temperature environment.

The cured product of a photocurable resin composition is, for example, a cured product obtained by "photoradical polymerization of the photocurable resin composition by irradiation with light in the atmosphere." The average reaction rate (hardening rate) of the entire cured product becomes 90 % or more (preferably 97% or more)" is hardened. The reaction rate of the entire cured product of the photocurable resin composition refers to the reaction rate measured on a cured product formed into a film with a thickness of 0.3 mm, for example.

Here, the so-called reaction rate refers to the ratio of the existing amount of (meth)acrylyl groups after light irradiation to the existing amount of (meth)acrylyl groups in the photocurable resin composition layer before light irradiation ( consumption ratio). The larger the value of the reaction rate, the higher the degree of reaction. Specifically, the reaction rate can be determined by comparing the absorption peak height (X) at 1640 to 1620 cm ^-1 from the reference line in the FT-IR measurement chart of the photocurable resin composition layer before light irradiation and after light irradiation. The absorption peak height (Y) at 1640 to 1620 cm ^-1 from the reference line in the FT-IR measurement chart of the photocurable resin composition layer (cured resin layer) is substituted into the following formula to calculate.

Reaction rate (%)=[(X-Y)/X]×100

FIG. 1 is a cross-sectional view showing an example of an image display device. FIG. 2 is a cross-sectional view showing an example of a polarizing plate used in an image display device. By using the photocurable resin composition of this embodiment for the cured resin layer 6 in the image display device 1 shown in FIG. 1 (see FIG. 1 ), for example, the moisture permeability of the cured resin layer 6 can be increased. It is considered that this makes it easier to discharge moisture generated by the polarizing plate 2 in a high-temperature environment to the outside of the image display device 1 through the hardened resin layer 6, thereby suppressing moisture generated by the polarizing plate 2 (for example, the protective layer 9 or the protective layer 2). 10) The generated moisture comes into contact with the polarizing element 8 . Therefore, discoloration of the polarizing plate 2 in the image display device 1 can be suppressed in a high-temperature environment.

Hereinafter, structural examples of the photocurable resin composition will be described. The photocurable resin composition is not particularly limited as long as it satisfies the above-mentioned moisture permeability conditions after curing. The photocurable resin composition is preferably composed of components that increase the moisture permeability of the cured product and have good compatibility. The photocurable resin composition preferably contains, for example, a (meth)acrylate resin, a monofunctional monomer, a photopolymerization initiator, a plasticizer, and an antioxidant. Here, (meth)acrylate includes both methacrylate and acrylate.

[(Meth)acrylate resin]

(Meth)acrylate resin is a photocurable resin (polymer) having two or more (meth)acryl groups in one molecule. From the viewpoint of compatibility, the (meth)acrylate resin preferably contains at least one of a polyether-based (meth)acrylic urethane resin and a polyester-based (meth)acrylic urethane resin. The (meth)acrylate resin may be a polymer or an oligomer.

Polyether-based (meth)acrylic urethane resin is a (meth)acrylic urethane resin having a polyether skeleton in the main chain. Specific examples include (meth)acrylic urethane oligomer having a polyether skeleton. things. Examples of commercially available products include Artresin UN-6200, UN-6202, UN-6300, and UN-6301 (the above are manufactured by Negami Industrial Co., Ltd.).

Polyester-based (meth)acrylic urethane resin is a (meth)acrylic urethane resin having a polyester skeleton in the main chain. Specific examples include (meth)acrylic urethane oligomer having a polyester skeleton. things. Examples of commercially available products include Artresin UN-7600 and UN-7700 (the above products are manufactured by Negami Industrial Co., Ltd.).

The weight average molecular weight of the (meth)acrylate resin is, for example, preferably 1,000 to 100,000, more preferably 5,000 to 40,000, and still more preferably 10,000 to 25,000.

In the photocurable resin composition, the content of the (meth)acrylate resin is preferably 5 to 50 mass %, more preferably 20 to 45 mass %. In particular, the total content of the polyether-based (meth)acrylic urethane resin and the polyester-based (meth)acrylic urethane resin is preferably 40% by mass or more relative to the total content of the (meth)acrylic ester resin. Preferably, it is 50 mass % or more, and more preferably, it is 80 mass % or more. One type of (meth)acrylate resin may be used alone, or two or more types may be used in combination. When two or more kinds of (meth)acrylate resins are used in combination, it is preferable that the total amount satisfies the above-mentioned content range.

[Monofunctional monomer]

The monofunctional monomer is, for example, a photocurable (meth)acrylate monomer. Furthermore, from the viewpoint of improving the moisture permeability of the cured product of the photocurable resin composition and the compatibility with other components, the monofunctional monomer is preferably a (meth)acrylate monomer containing a hydroxyl group. At least one type of monomer and heterocycle-containing (meth)acrylate monomer.

Specific examples of the hydroxyl-containing (meth)acrylate monomer include: (meth)acrylic acid 2-hydroxyethyl, (meth)acrylic acid 1-hydroxyethyl, (meth)acrylic acid 2-hydroxyethyl Propyl ester, 3-hydroxypropyl (meth)acrylate, 1-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, phenyl glycidyl ether (meth)acrylate, etc.

The heterocyclic ring in the heterocyclic-containing (meth)acrylate monomer preferably contains at least one of an oxygen atom or a nitrogen atom as a heteroatom. The heterocyclic ring is preferably a 3- to 8-membered ring, more preferably a 3 to 6-membered ring. The number of carbon atoms constituting the heterocyclic ring is preferably 2 to 6, more preferably 3 to 5. Heterocyclic rings may have a single ring structure or a polycyclic ring structure. The heterocyclic ring may have a substituent. Examples of substituents that the heterocyclic ring may have include methyl group, ethyl group, and the like.

As the heterocyclic-containing (meth)acrylate monomer, a (meth)acrylate containing a heterocyclic ring selected from the group consisting of a mofolin ring, a furan ring, and a dioxolane ring is preferred. . Specific examples include: acrylomorphine, (meth)acrylic acid tetrahydrofurfuryl ester, (meth)acrylic acid (2-methyl-2-ethyl-1,3-dioxolane) -4-yl) methyl ester, etc.

In the photocurable resin composition, the content of the monofunctional monomer is preferably 10 to 40 mass%, more preferably 20 to 40 mass%. In particular, the total content of the hydroxyl-containing (meth)acrylate monomer and the heterocycle-containing (meth)acrylate monomer is preferably 40% by mass or more, more preferably, relative to the total content of the monofunctional monomers. 50 mass % or more, and more preferably 80 mass % or more. One type of monofunctional monomer may be used alone, or two or more types may be used in combination. When two or more types of monofunctional monomers are used in combination, it is preferable that the total amount satisfies the above-mentioned content range.

[Photopolymerization initiator]

The photopolymerization initiator is preferably a photoradical polymerization initiator, and more preferably contains at least one of an alkylphenone-based photopolymerization initiator and a acylphosphine oxide-based photopolymerization initiator. As the alkylphenone-based photopolymerization initiator, 1-hydroxycyclohexylphenylketone (Irgacure 184, manufactured by BASF), 2-hydroxy-1-{4-[4-(2-hydroxy-2- Methyl-propyl)benzyl]phenyl}-2-methyl-1-propan-1-one (Irgacure 127, manufactured by BASF), etc. As the acylphosphine oxide-based photopolymerization initiator, 2,4,6-trimethylbenzyldiphenylphosphine oxide (Irgacure TPO, manufactured by BASF), etc. can be used. In addition, as a photopolymerization initiator, benzophenone, acetophenone, etc. can also be used.

The content of the photopolymerization initiator is preferably 0.1 to 5 parts by mass, more preferably 0.2 to 3 parts by mass relative to 100 parts by mass of the radically polymerizable components (the above-mentioned (meth)acrylate resin and monofunctional monomer). parts by mass. By setting this range, it is possible to more effectively prevent insufficient hardening during light irradiation and to more effectively prevent an increase in outgassing due to cracking. One type of photopolymerization initiator may be used alone, or two or more types may be used in combination. When two or more types of photopolymerization initiators are used in combination, it is preferable that the total amount satisfies the above range.

[Plasticizer]

For example, the plasticizer itself does not undergo photohardening due to light irradiation, and imparts flexibility to the cured resin layer after photocuring. From the viewpoint of compatibility with other components, the plasticizer preferably contains at least one of a polyether polyol and a polyester polyol.

As the polyether polyol, for example, a general polyether polyol obtained by adding an alkylene oxide to a initiator such as ethylene glycol, propylene glycol, glycerin, and trimethylolpropane and polymerizing the polyether polyol can be used. The alkylene oxide is not particularly limited, and examples thereof include ethylene oxide, propylene oxide, butylene oxide, and the like.

Examples of commercially available polyether polyols include "Adeka Polyether" manufactured by ADEKA Corporation. More specifically, "P series" which are polypropylene glycol, "BPX series" which are polypropylene glycol adducts of bisphenol A, "G series" which are polypropylene glycol adducts of glycerin, trihydroxyl series "T series" of polypropylene glycol adducts of methylpropane, "EDP series" of polypropylene glycol adducts of ethylenediamine, "SP series" of polypropylene glycol adducts of sorbitol, epoxy "PR series" which are random copolymers of ethane and propylene oxide, "CM series" which are propylene oxide-ethylene oxide block copolymers made by adding propylene glycol, etc.

The number average molecular weight of the polyether polyol is preferably, for example, 500 to 8000, more preferably 1000 to 5000.

As the polyester polyol, for example, a general polyester polyol obtained by polycondensation of a dicarboxylic acid and a diol can be used. Examples of dicarboxylic acids include aliphatic carboxylic acids such as adipic acid, azelaic acid, sebacic acid, and dodecanedioic acid; aromatic carboxylic acids such as terephthalic acid and isophthalic acid. Examples of diols include diols with a linear structure such as ethylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,9-nonanediol, and diethylene glycol; 1, 2-Propanediol, 1,3-butanediol, 2-methyl-1,3-propanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2,2-dimethyl-1 , 3-propanediol, 2-methyl-1,8-octanediol, etc.

Examples of commercially available polyester polyols include "P-1010", "P-2010", "P-3010", "P-2050" (the above are manufactured by Kuraray Corporation), "OD-X- 102", "OD-X-668", "OD-X-2068" (the above are manufactured by DIC Corporation), "NS-2400", "YT-101", "F7-67", "#50", " F1212-29", "YG-108", "V14-90", "Y65-55" (the above are manufactured by ADEKA), etc.

The number average molecular weight of the polyester polyol is, for example, preferably 500 to 8000, more preferably 1000 to 5000.

In the photocurable resin composition, the content of the plasticizer is preferably 15 to 50 mass%, more preferably 25 to 45 mass%. In particular, the total content of the polyether polyol and the polyester polyol relative to the total content of the plasticizer is preferably 40 mass% or more, more preferably 50 mass% or more, and still more preferably 80 mass% or more. One plasticizer may be used alone, or two or more plasticizers may be used in combination. When two or more plasticizers are used together, it is preferable that the total amount satisfies the above-mentioned content range.

[Antioxidants]

Antioxidants are used, for example, to prevent discoloration of the photocurable resin composition. The antioxidant is not particularly limited, and known antioxidants can be used. Examples include compounds having a hindered phenol structure, compounds having a hindered amine structure, compounds having a thioether structure, etc., and compounds having a hindered phenol structure are preferred.

Commercial products of compounds having a hindered phenol structure as examples of antioxidants include: "IRGANOX1010", "IRGANOX1035", "IRGANOX1076", "IRGANOX1098", "IRGANOX1135", "IRGANOX1330", "IRGANOX1726", " "IRGANOX1425WL", "IRGANOX1520L", "IRGANOX245", "IRGANOX259", "IRGANOX3114", "IRGANOX565", "IRGAMOD295" (the above are manufactured by BASF), etc.

In the photocurable resin composition, the antioxidant content is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 3 parts by mass. One type of antioxidant may be used alone, or two or more types may be used in combination. When two or more antioxidants are used in combination, it is preferable that the total amount satisfies the above-mentioned content range.

[Other ingredients]

The photocurable resin composition may further contain components other than the above-mentioned components within the range that does not impair the effect of "suppressing the discoloration of the polarizing plate in the image display device under high temperature environment." Examples of other components include thickeners and the like.

The photocurable resin composition is preferably liquid at normal temperature. For example, the photocurable resin composition preferably has a viscosity of 0.01 to 100 Pa‧s measured at 25°C using a B-type viscometer.

The photocurable resin composition preferably has a transmittance of 90% or more in the visible light region. Thereby, when forming the hardened resin layer, the visibility of the image formed on the image display member can be improved.

The refractive index of the photocurable resin composition is preferably substantially equal to the refractive index of the image display member or the translucent member, and for example, it is preferably 1.45 or more and 1.55 or less. Thereby, the brightness or contrast of the image light from the image display member can be improved, thereby improving visibility.

The photocurable resin composition can be prepared by uniformly mixing the above-mentioned components according to a known mixing method.

The photocurable resin composition of this embodiment has a moisture permeability of 400 g/m ² /day or more at a thickness of 0.3 mm after curing in an environment of 40°C and 90% relative humidity, thereby suppressing imaging in high temperature environments. The color change of the polarizing plate 2 in the display device 1.

<Image display device>

The image display device 1 of this embodiment is, for example, as shown in FIG. 1 , and includes an image display member 4 including a polarizing plate 2, a cured resin layer 6, and a translucent member 5 in this order. The moisture permeability of the hardened resin layer 6 when the thickness is 0.3mm is above 400g/m ² /day in an environment of 40°C and 90% relative humidity. By using the hardened resin layer 6 with such high moisture permeability, the discoloration of the polarizing plate 2 can be suppressed in a high temperature environment.

The image display member 4 is, for example, an image display panel in which a polarizing plate 2 is formed on the viewing side surface of the image display unit 3 . The image display member 4 is, for example, a liquid crystal display panel, an organic EL display panel, a touch panel, or the like. Here, the so-called touch panel refers to an image display and input panel that combines a display element such as a liquid crystal display panel and a position input device such as a touch panel.

Examples of the image display unit 3 include a liquid crystal unit or an organic EL unit. Examples of the liquid crystal cell include a reflective liquid crystal cell, a transmissive liquid crystal cell, and the like.

The polarizing plate 2 is, for example, as shown in FIG. 2 , and is a laminated body including a polarizing element 8 , a protective layer 9 provided on one side of the polarizing element 8 , and a protective layer 10 provided on the other side of the polarizing element 8 . The polarizing plate 2 may further include an adhesive layer (not shown) between the polarizing element 8 and the protective layer 9 and between the polarizing element 8 and the protective layer 10 . In addition, the polarizing plate 2 may further include other optical layers (such as a phase difference plate) in addition to the polarizing element 8 and the protective layers 9 and 10 .

As the polarizing element 8, for example, a polarizing plate of a known structure obtained by subjecting a polyvinyl alcohol-based resin to a dyeing treatment with a dichroic substance (for example, an iodine compound) and a stretching treatment can be used.

As the protective layers 9 and 10, for example, a film made of a thermoplastic resin excellent in transparency, mechanical strength, thermal stability, moisture barrier properties, isotropy, etc. can be used. Examples of such thermoplastic resins include cellulose resins such as triacetyl cellulose (TAC), polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), Polyether resin, polyurethane resin, polycarbonate resin, polyamide resin, polyimide resin, polyolefin resin, (meth)acrylic resin, cyclic polyolefin resin, polyarylate resin, polystyrene Resin, polyvinyl alcohol resin, and mixtures thereof.

The translucent member 5 only needs to have translucency so that the image formed on the image display member 4 can be viewed. Examples include plate-like materials or sheet-like materials such as glass, acrylic resin, polyethylene terephthalate, polyethylene naphthalate, and polycarbonate. Hard coating treatment, anti-reflection treatment, etc. can also be implemented on one or both sides of these materials. The physical properties such as thickness and elastic modulus of the translucent member 5 can be appropriately determined depending on the purpose of use. In addition, the translucent member 5 includes not only a relatively simple member as described above, but also a member formed by laminating various sheets or film materials such as a touch panel module.

A light-shielding layer 7 may also be provided on the peripheral portion of the translucent member 5 in order to improve the contrast of the image. The light-shielding layer 7 can be formed by applying, for example, a paint colored black or the like by a screen printing method, drying, and hardening. The thickness of the light shielding layer 7 is usually 5~100 μm.

The cured resin layer 6 is a cured product of the above-mentioned photocurable resin composition. The moisture permeability of the hardened resin layer 6 when the thickness is 0.3mm is above 400g/m ² /day in an environment of 40°C and 90% relative humidity. The preferable range of the water permeability of the cured resin layer 6 is the same as the range of the water permeability of the cured material of the above-mentioned photocurable resin composition.

The hardened resin layer 6 preferably has a transmittance of more than 90% in the visible light region. By satisfying this range, the visibility of the image formed on the image display member 4 can be improved. The refractive index of the hardened resin layer 6 is preferably substantially equal to the refractive index of the image display member 4 or the translucent member 5 . The refractive index of the hardened resin layer 6 is preferably 1.45 or more and 1.55 or less, for example. Thereby, the brightness or contrast of the image light from the image display member 4 can be improved, thereby improving the visibility. The thickness of the hardened resin layer 6 can be set to about 25 to 200 μm, for example.

The image display device 1 of this embodiment includes an image display member 4 including a polarizing plate 2, a cured resin layer 6, and a translucent member 5 in this order. The cured resin layer 6 has a moisture permeability at 40° C. when the thickness is 0.3 mm. In an environment with a humidity of 90%, it is above 400g/m ² /day. In this way, the image display device 1 is provided with the hardened resin layer 6 with high moisture permeability, thereby suppressing the discoloration of the polarizing plate 2 in a high temperature environment.

<Manufacturing method of image display device>

Hereinafter, the first embodiment and the second embodiment as specific examples of the manufacturing method of the image display device will be described. Furthermore, the same figure numbers in the drawings represent the same constituent elements.

[First Embodiment]

The manufacturing method of the first embodiment includes the following steps: (A) applying a photocurable resin composition to the surface of a translucent member; and combining the image display member and the translucent member through the light-blocking curable resin composition. The step of bonding the components (B); and the step of hardening the photocurable resin composition (C).

[Step (A)]

In step (A), for example, as shown in FIG. 3 , the photocurable resin composition 11 is applied to the surface of the translucent member 5 on the side where the light-shielding layer 7 is formed. The photocurable resin composition 11 has the same meaning as the photocurable resin composition described above, and the preferred ranges are also the same.

[Step (B)]

In step (B), for example, as shown in FIG. 4 , the light-transmitting member 5 is bonded to the polarizing plate 2 side of the image display member 4 through the light-blocking curable resin composition 11 . Thereby, the photocurable resin composition layer 12 is formed between the polarizing plate 2 and the translucent member 5 .

[Step (C)]

In step (C), for example, as shown in FIG. 5 , the photocurable resin composition layer 12 is irradiated with light (preferably ultraviolet rays) to harden the photocurable resin composition layer 12 . Thereby, as shown in FIG. 1 , the image display device 1 is obtained in which the image display member 4 and the translucent member 5 are laminated with the cured resin layer 6 interposed therebetween.

The light irradiation is preferably performed so that the reaction rate (hardening rate) of the hardened resin layer 6 becomes 90% or more, more preferably 95% or more. By satisfying this range, the visibility of the image formed on the image display member 4 can be improved. The reaction rate of the hardened resin layer 6 has the same meaning as the above-mentioned reaction rate.

The type, power, illuminance, cumulative light quantity, etc. of the light source used for light irradiation are not particularly limited. For example, the well-known photoradical polymerization process conditions of (meth)acrylate using ultraviolet irradiation can be used.

Furthermore, in the first embodiment, the photocurable resin composition 11 is applied to the surface of the translucent member 5, but the invention is not limited to this example. For example, in step (A), the photocurable resin composition 11 may be coated on the surface of the image display member 4 .

[Second Embodiment]

The manufacturing method of the second embodiment includes: a step of applying a photocurable resin composition to the surface of a translucent member (AA); and a step of temporarily curing the photocurable resin composition layer by irradiating it with light (BB ); the step of laminating the image display component and the translucent component via the temporarily hardened resin layer (CC); and the step of formally hardening the temporarily hardened resin layer (DD).

[Step (AA)]

In step (AA), for example, as shown in FIG. 6 , the photocurable resin composition 11 is coated on the surface of the translucent member 5 to form the photocurable resin composition layer 12 . Specifically, it is preferable to apply the photocurable resin composition 11 to the entire surface of the light-shielding member 5 on the side where the light-shielding layer 7 is formed, including the surface of the light-shielding layer 7 , so as to become flat. So that there is no step difference. The thickness of the photocurable resin composition layer 12 is, for example, preferably 1.2 to 50 times the thickness of the light shielding layer 7 , and more preferably 2 to 30 times the thickness. Coating of the photocurable resin composition 11 may be performed in such a manner as to obtain a necessary thickness, and may be performed once or multiple times.

[Step(BB)]

In step (BB), for example, as shown in FIG. 7 , the photocurable resin composition layer 12 formed in step (AA) is irradiated with light (preferably ultraviolet light) to temporarily cure, as shown in FIG. 8 The temporarily hardened resin layer 13 is formed.

The temporary hardening of the photocurable resin composition layer 12 is preferably performed so that the reaction rate of the temporarily hardened resin layer 13 becomes 10 to 80%, more preferably 40 to 80%. There are no particular restrictions on the conditions for light irradiation as long as the reaction rate of the temporarily cured resin layer 13 can be cured in such a manner that "the reaction rate of the temporarily cured resin layer 13 is preferably 10 to 80%."

[Step (CC)]

In step (CC), for example, as shown in FIG. 9 , the translucent member 5 is bonded to the image display member 4 via the temporarily hardened resin layer 13 . Bonding can be performed by applying pressure at 10 to 80° C. using a known pressure bonding device, for example.

[Step (DD)]

In step (DD), for example, as shown in FIG. 10 , the temporarily cured resin layer 13 is irradiated with light (preferably ultraviolet light) to cause it to be permanently cured. Thereby, the image display device 1 in which the image display member 4 and the translucent member 5 are laminated via the cured resin layer 6 can be obtained (see FIG. 1 ).

The formal hardening of the temporarily hardened resin layer 13 is preferably performed so that the reaction rate of the hardened resin layer 6 becomes 90% or more, more preferably 95% or more. There are no particular restrictions on the conditions for the actual curing as long as the curing can be performed in such a manner that "the reaction rate of the cured resin layer 6 becomes 90% or more."

Furthermore, in the second embodiment, the example in which the photocurable resin composition 11 is applied to the surface of the light-transmitting member 5 on the side where the light-shielding layer 7 is formed has been described. However, the image display member 4 may also be coated with the photocurable resin composition 11 . The photocurable resin composition 11 is coated on the surface.

In the above-mentioned manufacturing method of an image display device, the case where the translucent member 5 having the light-shielding layer 7 is used has been described, but the method is not limited to this example. For example, an image display device may be produced using a light-transmitting member without the light-shielding layer 7 .

In addition, as a manufacturing method of the image display device, a so-called dam and fill process may also be used. The dam filling process is, for example, the following method: using the dam material to form a coating area of the filler material on the surface of the image display component, coating the filler material in the coating area and separating the filler material to connect the image display component and the translucent component After lamination, the filler is irradiated with light to form a hardened resin layer.

Example

Hereinafter, embodiments of the present technology will be described.

[(Meth)acrylate resin]

Artresin UN-6202: polyether backbone acrylic urethane oligomer, manufactured by Negami Industrial Co., Ltd.

Artresin UN-7700: Polyester backbone acrylic urethane oligomer, manufactured by Negami Industrial Co., Ltd.

TE-2000: polybutadiene skeleton methacrylate urethane oligomer, manufactured by Soda Corporation of Japan

[Monofunctional monomer]

4HBA: 4-hydroxybutyl acrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd.

ACMO: Acrylamide, manufactured by KJ Chemicals

Viscoat#150: Tetrahydrofurfuryl acrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd.

MEDOL-10: (2-methyl-2-ethyl-1,3-dioxolan-4-yl)methyl acrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd.

New Frontier PGA: Phenyl glycidyl ether acrylate, manufactured by Daiichi Industrial Pharmaceutical Co., Ltd.

SR506: Isocamphenyl acrylate, manufactured by Arkema

[Plasticizer]

Adeka Polyether P-3000: polyether polyol, manufactured by ADEKA

Kuraray Polyol P-3010: Polyester polyol, manufactured by Kuraray Corporation

Krasol LBH-P3000: polybutadiene polyol, manufactured by Cray Valley Company

[Antioxidants]

Irganox1135: octyl 3-(4-hydroxy-3,5-diisopropylphenyl)propionate, manufactured by BASF

[Photopolymerization initiator]

Irgacure184: 1-hydroxycyclohexyl phenyl ketone, manufactured by BASF

[Preparation of photocurable resin composition]

The photocurable resin compositions of Examples and Comparative Examples were prepared by uniformly mixing each component in the blending amounts (parts by mass) shown in Table 1 below.

[Polarizing plate discoloration test]

As shown in FIG. 11 , a polarizing plate 18 (manufactured by Polatechno Co., Ltd.) including a TAC layer 14 with a thickness of 80 μm, a PVA layer 15 with a thickness of 30 μm, a TAC layer 16 with a thickness of 80 μm, and an acrylic adhesive layer 17 with a thickness of 25 μm is prepared in this order. ).

As shown in FIG. 12 , a glass plate 19 with a thickness of 1.1 mm is bonded to the polarizing plate 18 through the acrylic adhesive layer 17 . Furthermore, the photocurable resin composition 20 is dropped on the glass plate 19 to which the polarizing plate 18 is bonded, and the glass plate 21 with a thickness of 1.1 mm is placed on the dropped photocurable resin composition 20. Through the glass plate 21 The glass plate 21 is attached to its own weight. Thereby, the glass bonded body 22 is obtained.

Using an ultraviolet irradiation device, ultraviolet rays are irradiated from the glass plate 21 side of the glass joint 22 so that the cumulative light intensity becomes 5000 mJ/cm ² to cure the photocurable resin composition 20 to form the cured resin layer 23 , and obtain the result shown in FIG. 13 Image display device 24 for testing. The maximum thickness of the hardened resin layer 23 formed between the glass plate 19 and the glass plate 21 is approximately 0.3 mm. In addition, the thickness of the hardened resin layer 23 formed between the polarizing plate 18 and the glass plate 21 is 0.1 mm. The reaction rate of the hardened resin layer 23 is more than 90%.

The image display device 24 is placed in an environment of 100°C for 240 hours. Check visually whether the polarizing plate 18 in the image display device 24 is discolored after being left for 240 hours. When it is determined that the polarizing plate 18 is not discolored, it is evaluated as "○", and when it is determined that the polarizing plate 18 is discolored, it is evaluated as "×". The results are shown in Table 1.

[Moisture permeability test]

The moisture permeability of the hardened resin layer was measured in accordance with the moisture permeability test (moisture permeability cup method) of JISZ0208. The above-mentioned photocurable resin composition was irradiated with ultraviolet rays so that the cumulative light intensity became 5000 mJ/cm ² to prepare a cured resin layer with a thickness of 0.3 mm. As shown in Figure 14, the hardened resin layer 25 is placed in a cup 27 containing calcium chloride 26, placed in a constant temperature machine at 40°C and a relative humidity of 90%, and the calcium chloride 26 after being left for 24 hours is measured. By increasing the weight, the moisture permeability of the hardened resin layer 25 is obtained.

In addition, in the following table, "*" indicates that the photocurable resin composition is incompatible and various components are separated. As a result, a cured resin layer cannot be formed and each evaluation cannot be performed.

It can be seen that the moisture permeability of the photocurable resin composition used in the examples when the thickness after curing is 0.3 mm is more than 400g/m ² /day in an environment of 40°C and a relative humidity of 90%, so it can suppress the moisture in a high temperature environment. Discoloration of polarizing plates.

On the other hand, it was found that the moisture permeability of the photocurable resin compositions used in Comparative Examples 1, 2, and 6 when the thickness after curing was 0.3 mm did not reach 400 g/m ² / in an environment of 40° C. and a relative humidity of 90%. daw, so it is difficult to suppress the discoloration of polarizing plates in high temperature environments. Furthermore, since the photocurable resin compositions used in Comparative Examples 3 to 5 are incompatible, a cured resin layer cannot be formed, and the moisture permeability of the cured product and the discoloration of the polarizing plate cannot be evaluated.

1‧‧‧Image display device

2‧‧‧Polarizing plate

3‧‧‧Image display unit

4‧‧‧Image display component

5‧‧‧Transparent components

6‧‧‧Hardened resin layer

7‧‧‧Light shielding layer

100‧‧‧Image display device

101‧‧‧hardened resin layer

Claims (11)

A photocurable resin composition used for the cured resin layer in an image display device including an image display member, a cured resin layer, and a translucent member in this order, the image display member including a polarizing plate, and cured The moisture permeability of the above-mentioned photocurable resin composition when the thickness is 0.3mm is more than 400g/ ^m2 /day in an environment of 40°C and 90% relative humidity, and the above-mentioned photocurable resin composition contains (meth)acrylic acid Ester resin, monofunctional monomer, photopolymerization initiator and plasticizer. For example, the photocurable resin composition of claim 1, wherein the (meth)acrylate resin contains polyether (meth)acrylic urethane oligomer and polyester (meth)acrylic urethane. At least one type of oligomer. For example, in the photocurable resin composition of Item 1 or 2 of the patent application, the content of the above-mentioned (meth)acrylate resin is 5 to 50 mass%. For example, the photocurable resin composition of claim 1 or 2, wherein the above-mentioned monofunctional monomer contains a hydroxyl-containing (meth)acrylate monomer and a heterocyclic-containing (meth)acrylate monomer. At least 1 species. For example, in the photocurable resin composition of Item 1 or 2 of the patent application, the content of the above-mentioned monofunctional monomer is 10 to 40 mass%. For example, in the photocurable resin composition of claim 1 or 2, the plasticizer contains at least one of a polyether polyol and a polyester polyol. For example, in the photocurable resin composition of Item 1 or 2 of the patent application, the content of the above-mentioned plasticizer is 15 to 50 mass%. For example, the photocurable resin composition of Item 1 or 2 of the patent application further contains an antioxidant. For example, the photocurable resin composition of claim 1 or 2, wherein the above-mentioned image display member is an image display panel with a polarizing plate formed on the viewing side surface of the image display unit. An image display device, which includes an image display member, a hardened resin layer, and a light-transmitting member in this order. The image display member includes a polarizing plate, and the hardened resin layer has a moisture permeability of 40° C. and a relative humidity of 0.3 mm. It is more than 400g/m ² /day under 90% of the environment. The above-mentioned hardened resin layer is a hardened product of a photocurable resin composition. The above photocurable resin composition contains (meth)acrylate resin, monofunctional monomer, Photopolymerization initiator and plasticizer. A method of manufacturing an image display device, which includes the following steps: coating the photocurable resin composition of any one of items 1 to 9 of the patent application on the surface of a translucent member or an image including a polarizing plate the surface of the display member; laminating the image display member and the translucent member via the photocurable resin composition; and curing the photocurable resin composition.

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